Switch for high energy circuits



Sept. 26, 1967 R. T. CUSICK SWITCH FOR HIGH ENERGY CIRCUITS 2 Sheets-Sheet i Filed June 28, 1965 INVENTOR. RICHARD T: CUSICK ATTORNEY Sept. 26, 1967 R. T. CUSICK SWITCH FOR HIGH ENERGY CIRCUITS 2 Sheets-Sheet 2- Filed June 28, 1965 FIG. 2.

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INVENTOR. RICHARD T. CUSICK ATTORNEY United States Patent 3,344,248 SWITCH FOR HIGH ENERGY CIRCUITS Richard T. Cusick, Laurel, Md., assiguor to the United States of America as represented by the Secretary of the Navy Filed June 28, 1965, Ser. No. 467,798 18 Claims. (Cl. 200-82) ABSTRACT OF THE DISCLOSURE A switch for high energy circuits designed so as to avoid contact burning. The switch comprises a series of movable contact shoes mounted on a shaft which is caused to move by the action of hydraulic drive means, The contact shoes are attached to the shaft by a resilient springlike member which continually forces the contact shoes toward a bus bar after initial contact therebetween is made, thereby reducing contact bounce. To further reduce contact bounce, auxiliary contacts are fixedly mounted on the bus bar and serve to wedge the contact shoes toward the bus bar.

This invention relates generally to a switch and more particularly to a pneumatically operated switch for closing high energy circuits.

Switches of the type used in high energy circuits have a characteristically short life due to arcing. Complete destruction or fusion welding of the contacts is common where the making of the circuit has not been effectively performed. The most common deficiencies of existing switches reside in their slow initial reaction time and poor surface contact. Hitherto, an increase in the speed of circuit closing has produced an undesirable contact bounce, with resulting arcing.

It is therefore an object of this invention to provide a switch so constructed as to provide a suitable circuit closing device for high energy circuits.

Another object of this invention is to provide a switch having a short reaction time.

A still further object of this invention is to provide an efficient yet safe switch wherein contact is made in such a manner that contact life is substantially increased.

A further object of this invention is to provide an economical switch for high energy circuits.

An additional object of this invention is to provide a pneumatically operated switch.

An important object of this invention is to provide a switch in which contact bounce upon closing is eliminated.

Further objects and many of the attendant advantages of this invention will be readily apreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a front elevation of the switch; and

FIG. 2 is a side view of the device with the auxiliary contacts removed.

The circuit closing switch of the instant invention is adapted to be used in high energy circuits of the type utilized in supplying DC. power to plasma arc generators. It is contemplated that the instant switch will be used in circuits where 22,000 amperes is not uncommon and the voltage ranges up to 2200 volts.

The switch of the present invention includes first and second bus bar contacts having a lateral gap therebetween and each having swage block auxiliary contacts mounted thereon, a mounting shaft disposed between said first and second bus bar contacts for vertical movement into neutral and activated positions, a spring means encompassing said shaft and adapted to urge said shaft into said neutral position, drive means for urging said shaft in a vertical plane into said activated position, a laterally extending resilient conducting member attached to said mounting shaft, contact means connected to said conducting means and adapted to initially engage said bus bar contacts and subsequently move into engagement with said auxiliary contacts, and laterally extending resilient members attached to said mounting shaft and adapted to insure continuous contact between said contact means and said bus bar contacts.

Referring now to the drawings, the bus bar contacts 2 are supported by plastic or Glastex insulators 8 on supports 4 which are connected to a wall protection plate 6. Swage blocks or auxiliary contacts 9 are mounted on the bus bar contacts 2.. Disposed between the ends of the bus bars 2 is a mounting shaft 10. Attached to the upper portion of this shaft is an insulating member 12 of high strength glass fiber such as G-ltl which slides in a bushing 14 to guide the vertical motion of the shaft 10. The bushing 14 is attached to a bracket 16 mounted on the wall protection plate 6. The lower portion of the shaft is guided by a plate 18 which is attached to the Wall plate 6 by an insulating spacer 20. Connected to the lower end of the shaft is a second insulating member 23 which effectively insulates the shaft 10 from a shaft extension 10' which is connected to the lower portion of the insulating member 23. The shaft 10 enters a pneumatic cylinder 24 containing a piston (not shown) which is adapted to drive the shaft 10 downwardly.

Mounted on the shaft 10 near its upper end is a laterally extending resilient conducting member 26. The mounting shaft extends through the conducting member 26 medially of its length and width and is secured thereto by locking nuts 28. The member 26 is formed of thin plies of copper, is of generally bow-like configuration, and is connected at its extremities to contact shoes 30 by bolts 32. As shown in FIG. 2, four of the shoes 30- are connected to each end portion of the conducting member 26-.

The contact shoes 30 are formed with curved portions 34 which serve when initially brought into engagement with the bus bars 2 to make contact at lines shown (in cross-sections as points) by the arrows on the contact shoes 30, with lines shown (in cross-section as points) by the arrows on the bus bar 2, as shown in broken lines in FIG. 1. The curved or bus bar engaging areas 34 of the contact shoes 30 are formed of high heat resistant 50 percent silver and 50 percent tungsten alloy, which is necessary when initial contact is made.

When the shaft 10 is moved into its lower position, as shown in full lines in FIG. 1, the curved portions 34 of the contact shoes 30 will slide on the bus bar until the portions 35 of said shoes engage the swage blocks 9. The contact portions 35 are formed of a material containing percent silver and 20 percent tungsten, and are therefore of higher electrical conductivity than are bus bar engaging areas 34. This material is not required to be as resistant to heat as that used at the contact areas 34, since no initial contact is made between the contact portions 35 and the swage blocks 9, and consequently there is no excessive heat concentration or arcing in this area.

Also mounted centrally on the shaft 10 below the conducting member 26 are multiple leaf springs 36 which are held in position by lock nuts 38. The springs 36 are connected to the contact shoes 30 by bolts 40, and function to prevent any contact bounce. That is, when initial contact is made, the springs 36 operate to prevent the contact shoes 30 from rebouncing or breaking contact with the bus bars 2.

Encompassing the shaft 10 and engaging the plate 18 is a spring 42. A Washer 44 is positioned on the shaft 10 below the lower lock nut 38 to provide an adequate upper spring stop. The spring 42 is adapted to urge the shaft 3 and contacts toward the neutral, or open, position when the shaft is in its activated position. Upon failure of the pneumatic drive means the spring 42 will cause the switch to open, thereby providing inherent safety.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A switch for a high energy circuit, comprising first and second bus bar contacts, the surfaces of which are mutually parallel and having a gap therebetween, and each having an auxiliary contact mounted therea mounting shaft disposed between said first and second bus bar contacts and capable of vertical movement into neutral and activated positions,

spring means encompassing said shaft and adapted to urge said shaft into said neutral position,

drive means associated with said shaft and capable of urging said shaft in a vertical plane into said activated position,

a laterally exetnding resilient conducting means attached to said mounting shaft,

contact shoes connected to said conducting means and adapted to initially engage said bus bar contacts and subsequently move into engagement with said auxiliary contacts, and

laterally extending resilient members attached to said mounting shaft and said contact shoes, said resilient members being concave to said bus bar contacts while said shaft is in its neutral position and in a plane substantially parallel to the surfaces of said bus bar contacts while said shaft is in its activated position, and thereby adapted to insure continuous contact between said contact means and said bus bar contacts.

2. The invention as recited in claim 1, wherein each of said contact shoes comprises first and second contact surfaces.

3. The invention as described in claim 2, wherein said first contact surfaces comprise highly heat resistive material and said second contact surfaces comprise material having a lower heat resistance and a higher electrical conductivity than said first contact surfaces.

4. The invention as described in claim 3, wherein said first contact surfaces are arcuate and said second contact surfaces are planar.

5. A switch for closing high energy circuits, including a mounting plate,

a pair of spaced supports each secured to said mounting plate,

a pair of insulators each mounted on one of said supports,

first and second bus bar contacts each supported on one of said pair of insulators,

a pair of auxiliary contacts each secured to one of said bus bar contacts,

a mounting shaft disposed between said bus bar cona spring disposed about said mounting shaft and abutting said guide plate so'as to be able to exert an up- Wardly directed force on said mounting shaft,

a pneumatic cylinder,

a shaft extension connected to the lower end of said mounting shaft and insulated therefrom, said shaft extension being connected to said pneumatic cylinder and capable of being moved in a vertical direction thereby,

a laterally extending resilient conducting member connected to said mounting shaft beneath said cylindrical insulating member,

a plurality of contact shoes connected to the opposite end portions of said resilient conducting member and capable of engagement with said first and second bus bar contacts and said pair of auxiliary contacts so as to form an electrically conductive path between said first bus bar contact and its associated auxiliary contact and said second bus bar contact and its associated auxiliary contact, and

means connected to said mounting shaft and to each of said plurality of contact shoes for preventing bouncing of said contact shoes upon engagement with said first and second bus bar contacts.

.6. The invention as set forth in claim 5, wherein said contact bouncing preventing means comprises a plurality of leaf springs.

7. The invention as set forth in claim 5, wherein each of said contact shoes comprises first and second contact surfaces.

8. The invention as recited in claim 7, wherein said first contact surfaces comprise highly heat resistive material and said second contact surfaces comprise material having a lower heat resistance and a higher electrical conductivity than said first contact surfaces.

9. The invention as set forth in claim 8, wherein said first contact surfaces are arcuate and said second contact surfaces are planar.

10. In a switch for closing high energy circuits the combination including,

first and second bus bar contacts, the surfaces of which are mutually parallel,

first and second auxiliary contacts connected to said.

first and second bus bar contacts, respectively,

a mounting shaft,

a laterally extending resilient conducting member connected to said mounting shaft,

a plurality of contact shoes connected to the opposite end portions of said resilient conducting member, and means including laterally extending resilient members which are concave to said bus bar contacts while said shaft is in a first position and which lie in a plane substantially parallel to the surfaces of said bus bar contacts while said shaft is in a second position, said means being capable of urging said contact shoes to initially come into line contact with one of said bus bar contacts, slide therealong to thereby generate a planar contact, and subsequently engage one of said auxiliary contacts in planar contact.

11. The invention as described in claim 10, additionally including drive means for moving said mounting shaft in a vertical direction so as to enable said contact shoes to engage said bus bar contacts and said auxiliary contacts and maintain such engagement.

12. The invention as set forth in claim 11, additionally including means for providing rapid disengagement of said contact shoes from said first and second bus bar contacts and said first and second auxiliary contacts upon failure of said drive means.

13. The invention as recited in claim 12, wherein said disengaging means comprises a spring and said drive means comprises a pneumatic cylinder.

14. The invention as described in claim 10, wherein said contact shoes are each provided with first and second contact surfaces.

15. The invention as described in claim 14, wherein said first contact surfaces are arcuate and said second con tact surfaces are planar.

16. The invention as set forth in claim 14, wherein said first contact surfaces comprise highly heat resistive material and said second contact surfaces comprise material having a lower heat resistance and a higher electrical conductivity than said first contact surfaces.

17. The invention as recited in claim '16, additionally including drive means for moving said mounting shaft in a vertical direction so as to enable said contact shoes to engage said contacts and maintain such engagement.

18. A switch for closing high energy circuits, including a plurality of bus bar contacts, the surfaces of which are mutually parallel,

:a plurality of auxiliary contacts each connected to one of said plurality of bus bar contacts,

a mounting shaft,

resilient conducting means connected to said mounting shaft,

a plurality of contact shoes connected to said resilient conducting means, and means including laterally extending resilient members which are concave to said bus bar contacts while said shaft is in a first position and which lie in a plane substantially parallel to the surfaces of said bus bar contacts while said shaft is in a second position, said means being capable of urging said contact shoes to initially come into line contact with one of said plurality of bus bar contacts, slide therealong to thereby generate a planar contact from said line contact, and subsequently engage one of said plurality of auxiliary contacts in planar contact.

References Cited UNITED STATES PATENTS 1,843,615 2/1932 Lyle. 2,324,891 7/1943 Thumin 200146 2,352,550 6/1944 Joseph 200 146 2,392,201 1/ 1946 Thumin et al 200-146 2,766,348 10/ 1956 Forwald. 2,972,337 2/ 1961 Coggeshall 20'0-82 3,023,290 2/1962 Jennings.

FOREIGN PATENTS 534,643 4/ 1941 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner. 

1. A SWITCH FOR A HIGH ENERGY CIRCUIT, COMPRISING FIRST AND SECOND BUS BAR CONTACTS, THE SURFACES OF WHICH ARE MUTUALLY PARALLEL AND HAVING A GAP THEREBETWEEN, AND EACH HAVING AN AUXILIARY CONTACT MOUNTED THEREON, A MOUNTING SHAFT DISPOSED BETWEEN SAID FIRST AND SECOND BUS BAR CONTACTS AND CAPABLE OF VERTICAL MOVEMENT INTO NEUTRAL AND ACTIVATED POSITIONS, SPRING MEANS ENCOMPASSING SAID SHAFT AND ADAPTED TO URGE SAID SHAFT INTO SAID NEUTRAL POSITION, DRIVE MEANS ASSOCAITED WITH SAID SHAFT AND CAPABLE OF URGING SAID SHAFT IN A VERTICAL PLANE INTO SAID ACTIVATED POSITION, A LATERALLY EXTENDING RESILIENT CONDUCTING MEANS ATTACHED TO SAID MOUNTING SHAFT, CONTACT SHOES CONNECTED TO SAID CONDUCTING MEANS AND ADAPTED TO INITIALLY ENGAGE SAID BUS BAR CONTACTS AND 